The East Greenland Caledonides from the viewpoint of Receiver Functions, gravity and topography data

• Main Authors: Schiffer, Christian, Balling, N., Jacobsen, B. H., Nielsen, S.B.
• Format: Conference Object
• Language: English
• Published: 2012
• Subjects: East Greenland; Receiver Functions; Conjugate Margins; Caledonides; Geophysics; Geodynamics; Ella Ø; Greenland; Norway; Ice Sheet
• Online Access: https://pure.au.dk/portal/da/publications/the-east-greenland-caledonides-from-the-viewpoint-of-receiver-functions-gravity-and-topography-data(6a8a5db3-f20e-4227-acea-27704eeba9bb).html; https://pure.au.dk/ws/files/48303970/East_Greenland_Caledonides.pdf

The topography and crustal structure of the Caledonides were shaped by various events, including the Caledonian orogeny, lithospheric extensional collapse, continental breakup and erosional processes. Before the closure of the Iapetus Ocean (480 Ma), convergence of Laurentia, Baltica and Avalonia and the subsequent major collision and orogeny (420 Ma) the Caledonian deformation included several early stages of terrain accretion along the involved continents [1]. The high topographic elevation in the Caledonides and its longevity attract special attention, but also shallow extensional features, a lower crustal high velocity layer and the presence of a crustal root have to be considered. The understanding of this region includes the relationship of topography to crustal thickness in the background of isostatic compensation, as well as surface and subcrustal processes. For a period of 2 years (2009 to 2011) 11 temporary broadband stations were deployed and maintained by Aarhus University, forming the approximately 270 km long Ella-Ø-array. The profile extends from the Greenland ice sheet to the coastline, crossing the East Greenland Caledonides at about 73° north. The data are of high quality. P-S Receiver Functions, together with gravity and topography data are initially interpreted and compared with previous wide angle seismic studies in this area. The results show a generally landwards thickening crust and a decreasing Bouguer-gravity, mirroring the topography and hereby promoting the idea of the presence of a crustal root and mainly Airy type isostatic compensation. Furthermore a sub-moho eastward dipping structure is additionally observed in the Receiver Functions, possibly continuing to great depths. Its origin is not clarified yet, but might indicate the existence of a remnant collisional feature. The evolution of the East Greenland and Norwegian Caledonides along the conjugated margins is closely connected. Comparison with similar studies in Norway could give insight to what extent the areas might display similarities and correlation in topography and crustal structure, affected by a common geologic evolution and tectonic origin. References: [1] Roberts, D. 2003. The Scandinavian Caledonides: event chronology, paleogeographic settings and likely modern analogues. Tectonophysics, 365, 283 - 299